Unlocking the potential of ordinary Portland cement with hydration control additive enabling low-carbon building materials

Abstract

Ordinary Portland cement (OPC) is the core ingredient of many construction materials. In 2022, 4.1 billion tons were used worldwide, contributing to ~8% of CO2 emissions ( ~ 3 Gt/year). Nevertheless, the complete strength-generating capacity of OPC remains unrealized due to the restricted conversion of aluminates to ettringite, caused by conventional hydration kinetics. Here we show a hydration control additive that selectively modifies the hydration kinetics, thereby facilitating enhanced dissolution of aluminates (calcium aluminoferrite and tricalcium aluminate) in OPC, which promotes ettringite formation at a desired time. Increasing ettringite content improves packing of the hardened cement, resulting in ~50% higher specific strength and enabling cement reduction. It also increases OPC strength development efficiency, reducing carbon footprint by ~30%. The use of this additive can be combined with methods such as reducing water and/or using supplementary cementitious materials (SCMs) to prepare building materials with significantly fewer CO2 emissions than those from conventional OPC.